Wiper Operates (Lo Only)
WARNING: This page does not describe the selected car, but rather 10 other vehicles, including the 1990 GMC Vandura Special, 1990 GMC Vandura, 1990 GMC Rally Camper Special, 1990 GMC Rally, and 1990 GMC Magnavan. However, it is still accessible from the selected car via links, so may be relevant.
Leave wiring connected to wiper motor. Turn ignition on. Connect a jumper wire from terminal No. 17 to ground. See Figure . Turn wiper switch to HI position. If wiper runs at high speed, problem is an open wire from terminal No. 17 to dash switch. If wiper is inoperative, repair wiper motor.